This invention relates generally to temporary work platforms for oil and gas wells and more particularly to the adaptation of such work platforms directly to the well head for special operations such as removal and installation of coiled tubing, snubbing, injection and other service operations.
There exists in the oil and gas industry a procedure known as xe2x80x9csnubbingxe2x80x9d in which a string of pipe is forced into a well bore under pressure for various reasons, In such cases, the well bore usually has been drilled and a certain amount of casing has been set and blowout preventors or other ram apparatus have been installed at the wellhead to seal around the drill pipe or other pipe strings being inserted into the well bore. These blowout preventors and ram-type apparatus seal around the string of pipe being snubbed into the well under pressure to prevent the pressurized fluid from escaping around the outside of the string of pipe. The connections between the various pipe segments, including downhole tools, are made-up and snubbed into the well, and are usually immediately subjected to high external pressures. A leak in a connection creates a very hazardous working condition for all personnel involved as high-pressure fluids or gas may flow from the inside of the well bore, through the leak, upwardly through the string of pipe being snubbed into the well, and out onto the workmen. There also exists in the oil and gas industry a procedure known as the work-over of a well in which a string of pipe is forced into a previously drilled well. The well is xe2x80x9clivexe2x80x9d, that is, it contains fluid under pressure below a certain depth but because of some obstruction, such as sand or concrete or the like, contains little or no pressurized fluid above that depth. When the downhole tool on the end of the string of pipe breaks through the obstruction, the entire drill string, including the connections between the segments, is subject to the pressures of the well and such pressures can be intense. The same problems described above with respect to snubbing pipe into a completely live well are applicable to this work-over procedure. It is intended that the improved apparatus shall be applicable to such a work-over procedure and, as such, as used herein, the word snubbing shall include not only inserting a string of pipe into a completely live well but also inserting a string of pipe into a well under circumstances in which the possibility exists that the string of pipe may be subjected to pressurized fluids. It is an object of this invention to provide a safe work platform adaptable to the well head in a manner whereby the workers have access to all sides of the tubing injector through which a string of coiled tubing being snubbed into a well under pressure is forced, thereby reducing hazardous working conditions.
It is an additional object of this invention to provide an improved method and apparatus for personnel safety while snubbing a string of pipe into a well under pressure with a tubing injection apparatus whereby the apparatus is inserted in the wellhead piping above the blowout preventors or other ram-safety apparatus so that the connections between the pipe segments comprising the string of pipe may be inserted centrally through the work platform in a safe and efficient manner.
Still a further object of the invention is to provide a portable work platform centrally adaptable to a wellhead valve flange in a manner that provides unobstructed 360 degree access to the well bore and in a manner whereby a plurality of workers has access to the well head from the work platform and at least one of the workers is tethered to the platform at all times.
Yet another object of the invention is to provide a portable adaptor platform attached to and surrounding the well head that provides a secure place for hanging downhole tools, subsections, etc.
The invention itself, as well as additional objects and advantages thereof, will become readily apparent from the following description in connection with the accompanying drawings, in which like numerals represent like parts.
A portable work platform or basket adaptable to wellhead valve flanges at a point above the blowout preventors thereby providing 360-degree-personnel access to the wellhead during work-over and snubbing operations. The platform includes handrails, kick plates and an assortment of pipe flange adaptors for coupling to a variety of wellhead configurations. The platform further includes a pivotal arm for attaching a retractable personnel tether reel or a pulley block for a wench cable.